1. FIELD OF THE INVENTION
The present invention relates to a power transmitting V-belt and more particularly to a power transmitting V-belt which is used in combination with a variable diameter V-pulley.
2. DESCRIPTION OF THE PRIOR ART
Conventionally various kinds of examples have been disclosed as power transmitting V-belts of this type which are usable in combination with variable diameter V-pulleys for a vehicular V-belt type continuously variable transmission, for example.
Such V-belts are usually constructed by restraining and mounting a metal band, obtained from a plurality of laminated endless metal band elements, to a multiplicity of V-shaped metal blocks which are disposed adjacent to each other.
FIGS. 15 and 16 of the accompanying drawings show perspective views of one kind of V-shaped metal block and a stopper member for restraining and mounting a metal band to the V-shaped metal block, respectively, which have been disclosed by the present inventors in Japanese utility model application Kokai No. 79038/1985.
As shown in FIG. 15, a V-shaped metal block 4' according to this prior art has on its upper part a recessed groove 5' which opens upwardly and the bottom surface of the recessed groove 5' serves as a band supporting surface 5a' for receiving and supporting thereon the lower surface of a metal band 3' shown by one-dot-chain line. The opposite side surfaces of the V-shaped metal block 4' facing in the longitudinal direction of the metal band 3' are provided with semi-cylindrical recesses 8', 8', respectively. Cylindrical roller members, not shown, are interposed between and engaged in the opposed recesses 8', 8' of adjacent V-shaped metal blocks to obtain a connected or linked state of these blocks. Alternatively, the roller members may be omitted and a semi-cylindrical projection may be projected from one of the opposite side surfaces of the V-shaped metal block 4' in place of the recess. In this case, the connection or linkage between adjacent metal blocks is obtained by abutting the projection against the opposed recess of an adjacent metal block. The V-shaped metal block 4' is further provided with inclined parts 4a', 4a' on opposite end surfaces in the widthwise direction of the band 3'. The inclined parts 4a', 4a' come into engagement with a V-grooved surface of a V-pulley not shown.
In any of the afore-mentioned types, the conventional V-shaped metal block 4' includes, like the illustrated example, a pair of retaining grooves 9', 9' which open to upper wall parts 4b', 4b' disposed on the opposite ends of the metal block 4' in the widthwise direction of the band. By bringing opposite free ends of a stopper member 6' shown in FIG. 16 into engagement with the retaining grooves 9', 9', the metal band 3' is held on the band supporting surface 5a' of metal block 4'. More specifically, each retaining groove 9' comprises a longitudinal groove portion 9a' which extends in the longitudinal direction of the metal band 3' at a position above the inclined part 4a' and below a side surface 10' which is provided on each end of the metal block, a vertical groove portion 9b' extending upwards from a position near one end of the longitudinal groove portion 9a', and a lateral groove portion 9c' extending from the upper end of the vertical groove portion 9b' in the widthwise inward direction of the metal band 3' and opening to the recessed groove 5'. The lateral groove portion 9c' has the same width as the vertical groove portion 9b' and is open to the upper wall part 4b' over its whole length.
Each of the free ends of stopper member 6' which are engaged in the retaining grooves 9', 9' in assembly includes a longitudinal portion 6a' corresponding to the longitudinal groove portion 9a', a vertical portion 6b' standing upwards from one end of the longitudinal portion 6a' and corresponding to the vertical groove portion 9b', and a horizontal portion 6c' bent horizontally from the upper end of the vertical portion 6b ' and corresponding to the lateral groove portion 9c'. The horizontal portions 6c' and 6c ' of the pair of free ends are connected together via a central portion 6d' which is curved into a semi-circular shape. In case of the illustrated prior art structure, the free ends of stopper member 6' further include bent portions 6e', 6e' at tips of the longitudinal portions 6a', 6a', respectively.
Owing to the above-described arrangement, this prior art enjoys an advantage that the height of the upper wall part 4b', that is, the total height of the V-shaped metal block 4' can be reduced. However, it still suffers from the problem that the assembling process is troublesome, as will be discussed below in detail. That is, when mounting the stopper member 6' thus constructed to the V-shaped metal block 4', both the longitudinal portions 6a', 6a' of the member 6' are first expanded in its free state in the lateral opposite directions or in the directions apart from the central portion 6d' and the stopper member 6' is in such expanded state moved down from above onto the upper wall parts 4b', 4b' of V-shaped metal block 4' to cause longitudinal portions 6a', 6a' to slide down the pair of side surfaces 10', 10' of metal block 4'. The longitudinal portions 6a', 6a' are further moved down and brought into fitting engagement with the longitudinal groove portions 9a', 9a' which are at the lower ends of the side surfaces 10', 10'. Through this operation, the vertical portions 6b', 6b ' and horizontal portions 6c', 6c' also simultaneously come into engagement with the vertical groove portions 9b', 9b' and lateral groove portions 9c', 9c' of the retaining grooves 9', 9', whereby the stopper member 6' is fixed on the metal block 4'. In this assembled state, the bent portions 6e', 6e' provided at the tips of free ends of the stopper member 6' abut against that surface of the metal block 4' opposite to the surface on which the vertical groove portions 9b', 9b' are provided, thus restricting movements of the stopper member 6' in the longitudinal direction of the metal band 3'.
Since the opposite free ends of stopper member 6' are thus largely expanded at the time of assembling operation, if the member has been designed to have a relatively small resiliency, there may be encountered a case where expanding of the free ends exceeds the elastic limit thereof. Moreover, a large operational force and a skilled art are required for carrying out the assembling operation.
There has also been used instead of the afore-mentioned type of stopper member 6' such a stopper member that is devoid of bent portions 6e', 6e' at its free ends and is terminated by the longitudinal portions 6a', 6a'. When a stopper member of the latter type is mounted to the V-shaped metal block 4', it is not required to expand its free ends up to the full width between the side surfaces 10', 10' of metal block 4' but it is enough to expand them to the distance between the pair of vertical groove portions 9b', 9b'. The expanded free ends are engaged at their tips with the vertical groove portions 9b', 9b' and then the stopper member is forced downwards to a position near one end of each of the longitudinal groove portions 9a', 9a'. Thereafter, the tips of stopper member are pressed into the longitudinal groove portions 9a', 9a'.
The stopper member having no bent portions, however, still necessitates the step of expanding the member in a free state like the first-mentioned type and a dexterous operation is required for pushing the stopper member downwards along the vertical groove portions 9b', aligning the free end tips of the member with the longitudinal groove portions 9a' and forcing them into the groove portions 9a'.